Science Group
Explore subjects and practice MCQs
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Total MCQs
Science Group
Answer: Maxwell introduced the concept of displacement current to make Ampere\'s law consistent for time-varying fields.
Answer: Energy density u = ε₀E² = ε₀E₀² sin²(ωt-kx), proportional to the square of the amplitude.
Answer: Poynting vector S = E × B/μ₀ represents the directional energy flux (power per unit area) of the EM wave.
Answer: X-rays are produced when high-speed electrons are suddenly decelerated upon striking a metal target.
Answer: φ = hc/λ₀ = 12400/5000 = 2.48 eV
Answer: E₄/E₂ = (1/4²)/(1/2²) = (1/16)/(1/4) = 4/16 = 1/4. So E₄:E₂ = 1:4
Answer: Nuclear force is the strongest force in nature but operates only over very short range (~10⁻¹⁵ m).
Answer: In radioactive decay, the daughter nucleus has a different atomic number (and often different mass number) than the parent.
Answer: Electron spin was introduced to explain the fine structure of spectral lines and the anomalous Zeeman effect.
Answer: Pauli exclusion principle: no two electrons in an atom can have identical values of all four quantum numbers.
Answer: Δx · Δp ≥ h/4π. Position and momentum cannot both be known with arbitrary precision simultaneously.
Answer: |ψ|² gives the probability density, meaning the probability of finding the particle at a given location.
Answer: P/Q = R/S → 10/20 = 15/S → S = 30 Ω
Answer: Magnetic flux Φ = B·A, SI unit is Weber (Wb) = T·m²
Answer: Parallel currents attract and anti-parallel currents repel each other.
Answer: EM waves carry energy in both electric and magnetic fields, equally divided between them.
Answer: m₀c² = 9.109 × 10⁻³¹ × (3 × 10⁸)² / (1.6 × 10⁻¹³) ≈ 0.511 MeV
Answer: Gamma rays are the most penetrating because they are neutral, high-energy photons with no charge or mass.
Answer: Atomic number 2 means 2 protons; neutrons = mass number - protons = 3 - 2 = 1 neutron.
Answer: 1/λ = R(1/1² - 1/2²) = R(3/4) → λ = 4/(3R) ≈ 121.6 nm (Lyman alpha line).